Sealant composition for electronic device

ABSTRACT

The present invention provides a sealant composition for electronic device, in which the curing does not proceed when heated, which does not cause the problem of use in the mounting process of electronic device. The present invention relates to a sealant composition for electronic device comprising (a) a compound having two or more (meth)acryloyl groups and (c) a nitroxide compound and/or a thiocarbonylthio compound.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/JP2012/072987 filed Sep. 7, 2012, which claims priority toInternational Patent Application No. PCT/JP2011/070653, filed Sep. 9,2011, the contents of both of which are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to a composition to be usable forproducing an electronic device, particularly a semiconductor device, anduse of the same.

BACKGROUND OF THE INVENTION

As a mounting technology for a semiconductor chip, a flip chiptechnology, by which a semiconductor chip is directly connected onto asubstrate has been known. In the flip chip mounting, a semiconductorchip and a circuit substrate are connected by means of electrodes(bumps) formed on the element formation surface side of thesemiconductor chip. On this occasion, for the sake of reinforcement ofthe bonding parts and enhancement of the reliability of the connections,an underfill sealant, which is an adhesive composition, is generallyfilled between the semiconductor chip and the wiring substrate.

As an underfill composition, adhesive compositions containing anepoxy-based compound and/or a (meth)acrylic compound or the like havebeen known (e.g. Japanese Patent Laid-Open No. 2010-226098). Among them,a composition utilizing a radical curing reaction of a (meth)acryliccompound has an advantage over a composition containing an epoxy-basedcompound that the reaction rate is higher and the efficiency inproducing an electronic device can be enhanced.

As a method for filling an underfill sealant, it has been known that amethod in which a liquid adhesive composition is first applied on awiring substrate and then a semiconductor chip is mounted to conductsimultaneously electrode connection and sealing; a method (a so-calledcapillary method) in which electrical connection between an electrode ona semiconductor chip and a substrate is first established and then aliquid adhesive composition is applied on a side or a plurality of sidesof the chip for sealing the gap between the wiring substrate and thesemiconductor chip by capillarity and the like. By any of the methods,it is required to apply a liquid adhesive composition all over thewiring substrate, to fill the liquid adhesive composition uniformly inthe gap between the semiconductor chip and the wiring substrate, and thelike. Therefore, occasionally, a syringe which are used for applyingadhesive, the substrate and the like are heated to room temperature orhigher as needed in order to increase flowability of the adhesivecomposition.

However, there has been a problem in that, when an underfill sealantutilizing a radical curing reaction is used, a curing reaction of anunderfill composition may occasionally progress prematurely beforecarrying out sealing, which leads to inadequate electrode connection orpoor work efficiency. Such a problem tends to occur when an adhesivecomposition is in a state at room temperature or higher as describedabove. In order to overcome the problem, an additive is mixed in anunderfill sealant composition or the working temperature is lowered,which has not been sufficient. Consequently, further improvement of anadhesive composition to be used for an electronic device has been soughtafter.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the aforedescribedproblems in using a conventional adhesive composition and to provide acomposition which improves productivity of electronic devices. Further,another object is to provide an electronic device or an electronicappliance containing the composition.

The present invention relates to the following items.

1. A sealant composition for electronic device comprising:

-   -   (a) a compound having two or more (meth)acryloyl groups and    -   (c) a nitroxide compound and/or a thiocarbonylthio compound.

2. The composition according to the above item 1, further comprising aradical initiator.

3. The composition according to the above item 1 or 2, furthercomprising (b) a maleimide compound.

4. The composition according to the above item 3, wherein the maleimidecompound (b) comprises a bismaleimide.

5. The composition according to any one of the above items 1 to 4, whichis used as an underfill sealant.

6. The composition according to any one of the above items 1 to 5, whichis used in flip chip mounting.

7. An electronic device comprising a cured product of the compositionaccording to any one of the above items 1 to 6.

8. An electronic appliance comprising the electronic device according tothe above item 7.

The progress of the curing reaction of a composition according to thepresent invention at room temperature or higher and 80° C. or lower canbe suppressed adequately. Therefore, the progress of curing reactionduring flip chip mounting of a semiconductor chip is suppressed, andthus the composition of the present invention does not cause a defectiveelectrode connection during flip chip mounting of a semiconductor chipand sufficient working time in a mounting process can be secured. As theresult, a higher quality product can be provided without decreasing theproduction efficiency of an electronic device by flip chip mounting.

DETAILED DESCRIPTION OF THE INVENTION

A composition for an electronic device according to the presentinvention contains at least

(a) a compound having two or more (meth)acryloyl groups and

(c) a nitroxide compound and/or a thiocarbonylthio compound. Therespective components will be described below.

<(a) A Compound Having Two or More (Meth)Acryloyl Groups>

A composition of the present invention comprises a (meth)acryliccompound having two or more (meth)acryloyl groups (hereinafter, referredto as “component (a)”). Ordinarily, it is preferable that a compoundhaving one (meth)acryloyl group and/or a compound having three or more(meth)acryloyl groups is used as needed in addition to a compound havingtwo (meth)acryloyl groups. Further, the (meth)acrylic compound may be amonomer or an oligomer.

Although there is no particular restriction on a (meth)acrylic compoundusable for the present invention, examples of monofunctional compoundshaving a (meth)acryloyl group include phenylphenol acrylate,methoxypolyethylene acrylate, acryloyloxyethyl succinate, a aliphaticacrylate, methacryloyloxyethyl phthalic acid, phenoxyethylene glycolmethacrylate, a aliphatic methacrylate, β-carboxyethyl acrylate,isobornyl acrylate, isobutyl acrylate, tert-butyl acrylate, hydroxyethylacrylate, hydroxypropyl acrylate, dihydrocyclopentadiethyl acrylate,cyclohexyl methacrylate, tert-butyl methacrylate, dimethylaminoethylmethacrylate, diethylaminoethyl methacrylate, tert-butylaminoethylmethacrylate, 4-hydroxybutyl acrylate, tetrahydrofurfuryl acrylate,benzyl acrylate, ethylcarbitol acrylate, phenoxyethyl acrylate, andmethoxytriethylene glycol acrylate. Examples of compounds having two ormore (meth)acryloyl groups include hexanediol dimethacrylate,hydroxyacryloyloxypropyl methacrylate, hexanediol diacrylate, urethaneacrylate, epoxy acrylate, bisphenol A-type epoxy acrylate, modifiedepoxy acrylate, fatty acid-modified epoxy acrylate, amine-modifiedbisphenol A-type epoxy acrylate, allyl methacrylate, ethylene glycoldimethacrylate, diethylene glycol dimethacrylate, ethoxylated bisphenolA dimethacrylate, tricyclodecane dimethanol dimethacrylate, glycerinedimethacrylate, polypropylene glycol diacrylate, propoxylatedethoxylated bisphenol A diacrylate,9,9-bis(4-(2-acryloyloxyethoxy)phenyl)fluorene, tricyclodecanediacrylate, dipropylene glycol diacrylate, polypropylene glycoldiacrylate, propoxylated neopentyl glycol diacrylate, tricyclodecanedimethanol diacrylate, 1,12-dodecanediol dimethacrylate,trimethylolpropane trimethacrylate, dipentaerythtol polyacrylate,dipentaerythtol hexaacrylate, trimethylolpropane triacrylate,trimethylolpropane ethoxytriacrylate, polyether triacrylate, glycerinepropoxy triacrylate, pentaerythritol tetraacrylate,pentaerythritolethoxy tetraacrylate, ditrimethylol propanetetraacrylate, monopentaerythritol acrylate, dipentaerythritol acrylate,tripentaerythritol acrylate, polypentaerythritol acrylate, andpentaerythritol triacrylate.

Examples of commercial products of a (meth)acrylic compound usable forthe present invention include functional monomers of SR&CD series,functional epoxy acrylate oligomers and functional urethane acrylateoligomers of CN series from Sartomer, Co., Inc., Light Ester series, andLight Acrylate series from Kyoeisha Chemical Co., Ltd., and NK Esterfrom Shin-Nakamura Chemical Co., Ltd.

The (meth)acrylic compounds may be used singly or in a combination oftwo or more kinds thereof.

The content of a (meth)acrylic compound in accordance with the presentinvention may be adjusted depending on the purpose of use, and ispreferably from 10 to 90% by weight based on the total weight of acompound, and more preferably from 20 to 60% by weight. If the contentof a (meth)acrylate is within the range, the viscosity of a compositionbefore curing is low, and is superior in workability, and also instrength after curing.

<(c) Nitroxide Compound and/or Thiocarbonylthio Compound>

The composition according to the present invention contains a nitroxidecompound and/or a thiocarbonylthio compound (hereinafter, referred to as“component (c)”). A component (c) is a compound generally used as aregulating agent for regulating a growth reaction or a terminationreaction in a living radical polymerization.

A nitroxide compound means a compound having a nitroxide radical moietyrepresented by Formula (II) or a compound which can generate a nitroxideradical moiety. The nitroxide radical moiety of Formula (II) is known asa capping agent for capping a radical at a polymer growing end in aliving radical polymerization reaction mediated by nitroxide (NMP:Nitroxide-Mediated radical Polymerization).

Further, a thiocarbonylthio compound has a structure of Formula (III),and is known as a chain transfer agent for a RAFT (Reversible AdditionFragmentation chain Transfer) polymerization reaction, which is a kindof living radical polymerization.

When the composition according to the present invention is used forproducing a semiconductor device, the composition is, for example,applied on a wiring substrate as described below. In such an event, thecomposition is occasionally put in a state at room temperature or higherin order to increase flowability of the composition. On this occasion,since the composition according to the present invention contains acomponent (c), the progress of the curing reaction is suppressedadequately and the work efficiency at a succeeding mounting process isnot decreased. This is because, as presumed by the inventors, radicalsgenerated in the composition inactivate reversibly a growing radicalspecies with the radical structure of a component (c), and the progressof the curing reaction is suppressed thereby. In addition, thecomposition according to the present invention is not inhibited in thesubsequent curing reaction at a higher temperature, and does not cause aproblem in physical properties of a cured composition.

The content of a component (c) in the composition according to thepresent invention is preferably from 0.001 to 5% by weight based on thetotal weight of the composition, and more preferably from 0.01 to 1% byweight. Further, the composition according to the present inventionpreferably contains a thermal radical initiator described below, and inthis case the molar ratio of an initiator to a component (c)(initiator:component (c)) is preferably from 1:0.001 to 1:10, and morepreferably from 1:0.01 to 1:1. If the content of a component (c) iswithin the range, any problem in the reactivity or physical propertiesof a composition does not arise.

Although there is no particular restriction on a compound having anitroxide radical moiety, examples thereof include2,2,5-trimethyl-4-phenyl-3-azahexane-3-nitroxide,2,2,6,6-tetramethyl-1-piperidinyloxy radical (TEMPO),2,2,6,6-tetraethyl-1-piperidinyloxy radical,2,2,6,6-tetramethyl-4-oxo-1-piperidinyloxy radical,2,2,5,5-tetramethyl-1-pyrrolidinyloxy radical,1,1,3,3-tetramethyl-2-isoindolinyloxy radical, and N,N-di-t-butylaminoxyradical.

Examples of a compound which can generate a nitroxide radical moietyinclude alkoxyamine compounds represented by the following generalFormula (IV):

R¹—O—N(R²)(R³)  (IV)

wherein R¹, R², R³ are organic residues, and R² and R³ may together forma cyclic structure.

Examples of alkoxyamine compounds represented by the general Formula(IV) include the following alkoxyamine compounds as described in theresearch paper of Didier Benoit, et al. (J. Am. Chem. Soc., 1999, 121,p. 3904 to 3920), and the like.

The above compounds are available as commercial products, for example,from Sigma-Aldrich Co. LLC., and can be also synthesized by a publiclyknown method.

Examples of a thiocarbonylthio compound include compounds described inJapanese Laid-open Patent Publication No. 2004-518773. Specific examplesinclude, but not limited to, 2-cyano-2-propyl benzodithioate,4-cyano-4-(phenylcarbonothioylthio)pentanoic acid, 2-cyano-2-propyldodecyl trithiocarbonate,4-cyano-4-Rdodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid,2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid, cyanomethyldodecyl trithiocarbonate, cyanomethyl methyl(phenyl)carbamodithioate,bis(thiobenzoyl)disulfide, andbis(dodecylsulfanylthiocarbonyl)disulfide. The above are available ascommercial products, for example, from Sigma-Aldrich Co. LLC.

The compounds may be used singly or in combinations of two or more ofthe same as a component (c) for the composition according to the presentinvention.

<(b) Maleimide Compound>

A composition according to the present invention may preferably containfurther a (b) maleimide compound (hereinafter, referred to as “component(b)”) in addition to the (a) (meth)acrylic compound and the (c)nitroxide compound and/or a thiocarbonylthio compound. Although there isno particular restriction on a maleimide compound to be contained in acomposition according to the present invention, examples thereof includethe following compounds.

A maleimide compound has at least one, preferably one or two followingmoiety (I) in the molecule.

In the formula, R¹ and R² represent H, or a alkyl group having 1 to 6carbons; or R¹ and R² together represent an alkylene group having 2 to 6carbons. Preferably R¹ and R² are both H; or R¹ and R² togetherrepresent a 1,4-butylene group.

The maleimide compound is preferably liquid at room temperature andtherefore the moiety (I) bonds to a group that allows the maleimidecompound to be liquid, for example, an organic group having a branchedalkyl, alkylene, alkylene oxide, alkylene carboxyl, or alkylene amidestructure having sufficient length and branches to render the maleimidecompound liquid. The maleimide compound may have one, or two or morestructures (I). The compound having two of these groups is abismaleimide compound. In addition, a maleimide compound, even if it isnot liquid, may be used if the composition becomes liquid as being mixedwith another maleimide compound or mixed with another component.

Examples of a maleimide compound, in which the moiety (I) bonds to analkyl group or an alkylene group (the groups may have a double bond, ora saturated aliphatic ring), include the following compounds.

Particularly preferable examples include stearyl maleimide, oleylmaleimide, behenyl maleimide, and a 1,20-bismaleimide derivative of10,11-dioctyleicosane, as well as a combination thereof. A1,20-bismaleimide derivative of 10,11-dioctyleicosane is available fromHenkel AG & Co. under a product name of X-BMI, which is synthesized from1,20-diamino-10,11-dioctyl-eicosane and/or a diamine of a cyclic isomerthereof by a method according to U.S. Pat. No. 5,973,166 (the entiredisclosures of U.S. Pat. No. 5,973,166 are incorporated herein byreference). X-BMI contains one, or two or more of1,20-bismaleimide-10,11-dioctyl-eicosane [compound denoted by Formula(X-1)], 1-heptylene maleimide-2-octylenemaleimide-4-octyl-5-heptylcyclohexane [compound denoted by Formula(X-2)], 1,2-dioctylene maleimide-3-octyl-4-hexylcyclohexane [compounddenoted by Formula (X-3)], and the like. Bismaleimide compounds denotedby formulas (X-1) to (X-3) may be also preferably used solely.

Examples of a maleimide compound, in which the moiety (I) is bonded witha group having an alkylene oxide structure, include the followingcompounds.

In the formula, R is an alkylene group, preferably ethylene or1,2-propylene, and n is an integer from 2 to about 40, wherein themagnitude of an integer and the distribution of n to render the compoundliquid are selected preferably. The compound is available from DICCorporation as LUMICURE (registered trademark) MIA200.

Examples of another usable maleimide compound include a compound(3,4,5,6-tetrahydrophthaloimide ethyl acrylate) denoted by the followingformula.

The above maleimide compounds may be used singly or in a combination oftwo or more kinds thereof.

The content of a maleimide compound in accordance with the presentinvention is preferably from 0 to 50% by weight based on the totalweight of a composition, more preferably from 0.1 to 50% by weight, andfurther preferably from 1 to 20% by weight. If the content of amaleimide compound is within the range, the curing rate becomessuperior.

Meanwhile, when a composition contains a maleimide compound inaccordance with the present invention, the (meth)acrylic compound andthe maleimide compound in a composition polymerize by a radical reactionby being heated to a predetermined temperature. In this case, only 1kind of compound may polymerize to form a homopolymer, or two or morekinds of compounds may polymerize to form a copolymer.

<Filler>

A composition according to the present invention may contain a filler.By blending a filler, a composition for an electronic device having alow coefficient of linear expansion exhibiting superior dimensionalstability and improved flame resistance can be obtained. As a filler,either of an insulating inorganic filler or an electrically conductiveinorganic filler may be selected depending on the purpose of use.Examples of an insulating inorganic filler include silica, calciumsilicate, aluminum hydroxide, magnesium hydroxide, calcium carbonate,magnesium carbonate, magnesium oxide, aluminum nitride, and boronnitride, and particularly silica is preferable. Examples of anelectrically conductive inorganic filler include a metal and carbonblack.

Further, a filler subjected to a surface modification according to needmay be also used. Examples of commercial products include a lineup of“Mitsubishi carbon black” from Mitsubishi Chemical Corporation, “Asahi”series from Asahi Carbon Co., Ltd., calcium silicate “PCM Lite” series,aluminum hydroxide “ALH” series, and alumina-based “Celasule” from KawaiLime Ind. Co., Ltd., titanium oxide “STR series”, silica “SciqusSeries”, zinc oxide “FINEEX series”, magnesium oxide “SMO Series”, andzirconium oxide “STR Series” from Sakai Chemical Industry Co., Ltd.,silica, oxidized alumina “ADMAFINE” series from Admatechs CompanyLimited, silica “SNOWTEX” series from Nissan Chemical Ind., Ltd., and ametallic oxide containing silica and aluminum oxide “NanoTek” seriesfrom C.I. Kasei Co., Ltd.

When a composition according to the present invention is used forproducing, for example, a semiconductor device, the average particlediameter of a filler is preferably smaller than the gap dimensionbetween a semiconductor chip element formation surface and a wiringsubstrate. If the average particle diameter of a filler is too large,the filler may be trapped between metal connections in producing asemiconductor device, so that good electrical reliability may not beestablished, or a chip may break.

Although the blending amount of a filler may be adjustable depending onthe purpose of use, it is preferably, for example, from 1 to 99% byweight based on the total weight of an adhesive composition, and morepreferably from 10 to 80% by weight. If the content is within the range,a composition having a sufficient effect of filler addition and aviscosity free from any problem in handling can be obtained.

<Radical Initiator>

A composition according to the present invention contains preferably aradical initiator, more preferably a thermal radical initiator. As athermal radical initiator, an organic peroxide is preferable, and onethat generates a radical at a convenient temperature is selected.

Although there is no particular restriction on a radical initiator,examples thereof include diisobutyl peroxide, cumyl peroxyneodecanate,di-n-propyl peroxycarbonate, diisopropyl peroxycarbonate, di-sec-butylperoxycarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanate,di(4-t-butylcyclohexyl)peroxydicarbonate,di(2-ethylhexyl)peroxydicarbonate, t-hexyl peroxyneodecanate, t-butylperoxyneodecanate, t-butyl peroxyneoheptanate, t-hexyl peroxypivalate,t-butyl peroxypivalate, di(3,5,5-trimethylhexanoyl)peroxide, dilauroylperoxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethyl hexanate, disuccinicacid peroxide, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethyl hexanate, di(4-methyl benzoyl)peroxide,t-butylperoxy-2-ethyl hexanate, dibenzoyl peroxide,1,1-di(t-butylperoxy)-2-methylcyclohexane,1,1-di(t-hexylperoxy)-3,3,5-trimethyl cyclohexane,1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane,2,2-di(4,4-di-(t-butylperoxy)cyclohexyl)propane, t-hexylperoxy isopropylmonocarbonate, t-butyl peroxymaleic acid, t-butyl peroxy-3,5,5-trimethylhexanate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate,t-butylperoxy 2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate,2,5-di-methyl-2,5-di(benzoyl peroxy)hexane, t-butyl peroxyacetate,2,2-di(t-butylperoxy)butane, t-butyl peroxybenzoate,n-butyl-4,4-di-(t-butylperoxy)valerate, di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, di-t-hexyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, p-menthane hydroperoxide,2,5-dimethyl-2,5-di(t-butylperoxy)hexane-3,3,5-diisopropylbenzenehydroperoxide, 1,1,3,3-tetramethyl butyl hydroperoxide, cumenehydroperoxide, t-butyl hydroperoxide, and 2,3-dimethyl-2,3-diphenylbutane. The organic peroxides can be purchased from Akzo Nobel N.V., Giospecialities Chemical, Arkema S.A., NOF Corporation, Kayaku AkzoCorporation, and the like. The same may be used singly, or in acombination of two or more kinds thereof.

The blending amount of a radical initiator is preferably from 0.01 to10% by weight based on the total weight of a composition, and morepreferably from 0.1 to 5% by weight. If the blending amount of a thermalradical initiator is within the range, there occurs no problem ofinstability in applying the composition or of prolongation of a curingtime.

In addition to the aforedescribed components, a composition according tothe present invention may contain an additive as needed, such as asilane coupling agent, a rubber component, an antioxidant, a lightstabilizer, a radical stabilizing agent, and a surfactant. A silanecoupling agent and a rubber component can advantageously improve theadhesive property of a composition, relax a stress, and reduce warpingof a cured reaction product. Meanwhile, an antioxidant, and a radicalstabilizing agent may be used in order to extend the pot life. Asurfactant may be added for defoaming in coating, or for improving thewettability to a target to be coated and the leveling property.

By blending a silane coupling agent to a composition the adhesiveproperty of an adhesive can be improved.

Although there is no particular restriction on a silane coupling agent,examples thereof include an aminosilane coupling agent, an epoxy silanecoupling agent, a ureide silane coupling agent, an isocyanate silanecoupling agent, a vinyl silane coupling agent, a (meth)acrylic silanecoupling agent, and a ketimine silane coupling agent, and among these,an isocyanate silane coupling agent, a (meth)acrylic silane couplingagent, and an epoxy silane coupling agent are preferable. The silanecoupling agents can be purchased from Dow Corning Toray Silicone Co.,Ltd., Shin-Etsu Silicone, Matsumoto Fine Chemical Co., Ltd., TokyoChemical Industry Co., Ltd. and the like.

Although the blending amount of a silane coupling agent is adjustableappropriately, it is preferably, for example, from 0 to 10% by weightbased on the total weight of a composition, and more preferably from 0to 5% by weight. If the content of a silane coupling agent is too high,a silane coupling agent vaporizes during thermal compression bonding ina flip chip process to develop voids.

Although there is no particular restriction on rubber, examples thereofinclude industrial rubbers, such as acrylic rubber, nitrile rubber,butadiene rubber, and nitrile butadiene rubber, and a low molecularweight crosslinking agent for rubber. Examples of commercial productsfor industrial rubbers include “Paracron RP” series from Negami ChemicalIndustrial Co., Ltd., “Staphyloid IM” series and “Staphyloid AC” seriesfrom Ganz Chemical Co., Ltd., “Zeon” series from Zeon Kasei Co., Ltd.,and “METABLEN C/E/W/S/SX/SRX” from Mitsubishi Rayon Co., Ltd. Examplesof commercial products for a low molecular weight crosslinking agent forrubber include “Ricon” series from Sartomer, “Poly bd” and “Poly ip”series, “EPOL” series, and “Krasol” from Idemitsu Kosan Co., Ltd., and“NISSO-PB” from Nippon Soda Co., Ltd. The products may be used singly orin a combination of two or more kinds thereof.

Further, a commercial product of an acrylic resin, in which a rubberparticle has been dispersed in advance, may be used, and examplesthereof include Paracron SN-50, AS-3000, ME-2000, W-1163, W-248E,W-197C, PRE-COAT 200, and PANLON S-2012 from Negami Chemical IndustrialCo., Ltd.

Although the blending amount of rubber is adjustable appropriately, itis preferably, for example, from 0 to 30% by weight based on the totalweight of an adhesive composition, and more preferably from 0 to 20% byweight. If the rubber content is too high, the viscosity of an adhesivecomposition increases too much causing such problems that the handlingproperty may be deteriorated, or mixing of other components may becomedifficult, or the adhesiveness of an adhesive may be deteriorated.

Examples include for an antioxidant and a radical stabilizing agenthydroquinones, benzoquinones, and hindered phenols; and for a lightstabilizer benzotriazole-based, triazine-based, benzophenone-based,benzoate-based, and hindered amine-based ultraviolet absorbers. Asurfactant may be selected out of catalogs of commercial productsdepending on a purpose of use.

<Production Method of Composition for Electronic Device>

A composition according to the present invention can be obtained bymixing uniformly the above specified respective components, as well as asolvent according to need. A composition is only required that aviscosity thereof is adjusted as long as it can be applied by a coatersuch as a dispenser, and may be also solventless. It is also possible toadjust viscosity by selection of compounds in a composition, or byadjustment of the blending amounts thereof. A composition according tothe present invention can be produced by kneading uniformlypredetermined amounts of the respective components by, withoutlimitation thereto, using singly or in a combination of publicly knownvarious kneading machines, such as a homodisperser, a universal mixer, aBanbury mixer, a kneader, a twin roll mill, a triple roll mill, and anextruder. Kneading may be conducted under various conditions, such as atnormal temperature or with heating, at a normal pressure, a reducedpressure, or an increased pressure, or with inert gas flow.

The composition for an electronic device according to the presentinvention is preferably used as a sealant for an electronic device,without particular restriction thereto. In this regard, examples of asealant include an underfill sealant (sealant) for an electronic deviceincluding a semiconductor chip, an insulating varnish, an insulatingmaterial for a printed wiring substrate, an impregnation resin for aprinted wiring substrate, a coating material for an electronic device, apotting material for an electronic device, and an adhesive for anelectronic device. It is particularly preferable that the presentinvention is directed to use as an underfill sealant.

<Electronic Device and Production Method of the Same>

Next, a production method of an electronic device comprising acomposition according to the present invention will be described.Although there is no particular restriction on a production method of anelectronic device, a flip chip process is preferably used. In a flipchip process, it is particularly preferable to coat a circuit face of awiring substrate with a composition according to the present invention.A production method of an electronic device comprises, for example,

(1) a coating process for coating a circuit face of a wiring substratewith a composition according to the present invention, and

(2) a bonding and sealing process for placing a semiconductor chip onthe composition applied on the wiring substrate, and performingelectrical connection between the semiconductor chip and the wiringsubstrate and seal of a gap therebetween. The respective processes willbe described below.

<(1) Coating Process>

In the coating process, a composition according to the present inventionis applied on a circuit face of a wiring substrate. All over the surfaceof a wiring substrate or only a part where a semiconductor chip is to bemounted may be coated with the composition. Examples of a coating methodinclude coating methods using a spin coater, a dispenser, a roller, andthe like and screen printing. In this connection, a syringe used in thecoating process, a substrate, and the like may be heated to roomtemperature or higher as needed so as to improve the flowability of thecomposition.

<(2) Bonding and Sealing Process>

In the bonding and sealing process, electrical connection between thesemiconductor element and the wiring substrate is performed, andsimultaneously a gap between the semiconductor element and the circuitsubstrate is sealed with a composition according to the presentinvention to produce an electronic device. Firstly, a semiconductor chipis placed on a part coated with an adhesive composition on a wiringsubstrate. On this occasion, a circuit face of the wiring substrate(namely, a face coated with the composition in the coating process) andan element formation surface of the semiconductor chip are so alignedthat the two face each other. Then, thermal compression bonding isfollowed. Heating may be performed additionally after the thermalcompression bonding in order to cure the adhesive composition. Ingeneral, as a method for thermal compression bonding and connection,thermal compression bonding is performed immediately after positionadjustment using a flip chip bonder, or after position adjustment andprovisional mounting, heating connection is performed in a reflow oven,and the like. On this occasion, a thermal profile suitable for a packageor a sealing method is applied. Further, for chip mounting, not only aflip chip bonder, a die bonder, and the like, with which positionadjustment is possible, may be also used alternatively.

There is no particular restriction on the temperature for thermalcompression bonding. When an electrode is a solder bump or a solder capbump, a temperature higher than the melting point by 10 to 100° C. ispreferable, 200° C. or higher is preferable, and 210 to 300° C. is morepreferable. The duration time for thermal compression bonding ispreferably from 1 to 20 sec, and the pressure is preferably from 0.1 to7 MPa. Further, if additional heating is performed for curing completelyan adhesive composition after the thermal compression bonding, forexample, 150 to 220° C. for 30 to 180 min are preferable.

An electronic device obtained as above can be applied to variouselectronic appliances utilizing a semiconductor chip, such as a cellphone, a personal computer, and a TV.

EXAMPLES

The present invention will be described below in more details by way ofExamples. However, the present invention is not restricted by thefollowing Examples.

Table 1 shows compounds used in the following Examples and ComparativeExamples.

TABLE 1 Component Name of source material Description of compound(Meth)acrylate CN120 (produced by Sartomer) Epoxy acrylate oligomerSR9003 (produced by Sartomer) Propoxylated neopentyl glycol diacrylateSR480 (produced by Sartomer) Ethoxylated bisphenol A dimethacrylateSR444 (produced by Sartomer) Pentaerythritol triacrylate MaleimideLUMICURE MIA200 produced byDIC Corporation Polyalkylene maleimideacetate Thermal radical Perbutyl Z (produced by NOF Corporation) t-butylperoxybenzoate initiator Filler SE-2030(produced by Admatechs Co., Ltd.)Silica Coupling agent KBM-503(produced by Shin-Etsu Chemical Co., Ltd.)3-Methacryloxypropyltrimethoxysilane Nitroxide radical N-1 (Produced bySigma-Aldrich Co. LLC.) N-tert-butyl-N-(2-methyl-1-phenylpropyl)-O-(1-compound phenylethyl)hydroxylamine (compound represented by Formula V)N-2 (Produced by Sigma-Aldrich Co. LLC.)2,2,5-Trimethyl-4-phenyl-3-azahexane-3-nitroxide N-3 (Produced bySigma-Aldrich Co. LLC.) TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxyradical) Thiocarbonylthio S-1 (Produced by Sigma-Aldrich Co. LLC.)2-Cyano-2-propyl benzodithioate radical compound S-2 (Produced bySigma-Aldrich Co. LLC.) 4-Cyano-4-(phenylcarbonothioylthio)pentanoicacid S-3 (Produced by Sigma-Aldrich Co. LLC.) 2-Cyano-2-propyl dodecyltrithiocarbonate S-4 (Produced by Sigma-Aldrich Co. LLC.) 4-Cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid S-5 (Produced bySigma-Aldrich Co. LLC.)2-(Dodecylthiocarbonothioylthio)-2-methylpropionic acid S-6 (Produced bySigma-Aldrich Co. LLC.) Cyanomethyl dodecyl trithiocarbonate S-7(Produced by Sigma-Aldrich Co. LLC.) Cyanomethylmethyl(phenyl)carbamodithioate S-8 (Produced by Sigma-Aldrich Co. LLC.)Bis(thiobenzoyl) disulfide S-9 (Produced by Sigma-Aldrich Co. LLC.)Bis(dodecylsulfanylthiocarbonyl) disulfide Polymerization Benzoquinone(Produced by Tokyo Chemical Industry inhibitor Co., Ltd.) Hydroquinone(Produced by Tokyo Chemical Industry Co., Ltd.)

Apparatus, and the like used in the following Examples and ComparativeExamples are as follows:

(1) Circuit substrate: WALTS-KIT MB50-0102JY_CR from Waits Co., Ltd.Pads are according to CuOSP specifications.

(2) Semiconductor chip: WALTS-TEG MB50-0101JY with 544 bumps constitutedwith a Cu pillar and solder from Waits Co., Ltd.

(The circuit substrate (1) and the semiconductor chip (2) are connectedtogether to form a daisy chain, and when all the bumps in a chip areconnected, the continuity can be established. In other words, if asingle bump out of 544 bumps cannot be connected, electrical insulationis recognized by an electrical continuity test.)

<Preparation of Adhesive Composition for Underfill Sealant>

The relevant components were mixed by the following method to prepare anadhesive composition. Table 2 shows compounds blended in the respectiveExamples and Comparative Examples and the blending amounts thereof (% byweight).

TABLE 2 Example Comparative Example 1 2 3 4 5 6 7 8 9 10 11 12 13 1 2 34 (Meth)acrylic CN120 5 5 5 5 5 5 5 5 5 5 5 5 15 6.1 5.1 5 5 compoundSR9003 10 10 10 10 10 10 10 10 10 10 10 10 10 13 10 10 10 (ComponentSR480 10 10 10 10 10 10 10 10 10 10 10 10 10 13 10 10 10 (a)) SR444 1010 10 10 10 10 10 10 10 10 10 10 10 13 10 10 10 Maleimide MIA200 10 1010 10 10 10 10 10 10 10 10 10 0 0 10 10 10 compound (Compo- nent(b))Coupling agent KBM-503 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.30.3 0.3 0.3 0.3 0.3 Filler SE2030 54.4 54.4 54.4 54.4 54.4 54.4 54.454.4 54.4 54.4 54.4 54.4 54.4 54.4 54.4 54.4 54.4 Radical Perbutyl Z 0.20.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2initiator Radical N-1 0.1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 stabilizer N-20 0.1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (Compo- N-3 0 0 0.1 0 0 0 0 0 0 0 00 0 0 0 0 0 nent(c)) S-1 0 0 0 0.1 0 0 0 0 0 0 0 0 0 0 0 0 0 S-2 0 0 0 00.1 0 0 0 0 0 0 0 0 0 0 0 0 S-3 0 0 0 0 0 0.1 0 0 0 0 0 0 0 0 0 0 0 S-40 0 0 0 0 0 0.1 0 0 0 0 0 0 0 0 0 0 S-5 0 0 0 0 0 0 0 0.1 0 0 0 0 0 0 00 0 S-6 0 0 0 0 0 0 0 0 0.1 0 0 0 0 0 0 0 0 S-7 0 0 0 0 0 0 0 0 0 0.1 00 0 0 0 0 0 S-8 0 0 0 0 0 0 0 0 0 0 0.1 0 0 0 0 0 0 S-9 0 0 0 0 0 0 0 00 0 0 0.1 0.1 0 0 0 0 Polymeri- Benzo- 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.10 zation quinone inhibitor Hydro- 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.1quinone Total 100 100 100 100 100 100 100 100 100 100 100 100 100 100100 100 100 (The unit of the number is weight %.)

Example 1 Preparation of Composition

Compounds listed in Table 2 were weighed out according to the designatedblending amounts and kneaded uniformly by a triple roll mill. Theproduct was degassed in vacuum to prepare an adhesive composition A.

After heating a circuit substrate in an oven at 120° C. for 1 hour, thecomposition A was applied on a circuit substrate with an autodispenserto obtain a circuit substrate B coated with the adhesive composition A.

(Mounting of Electronic Device)

Immediately after preparation of the circuit substrate B (heat exposuretime 0 min), or after being left standing on a hot plate at 80° C. for15 min, 30 min, 45 min, 60 min, or 90 min, the position of asemiconductor chip and the circuit substrate B was adjusted and the twowere pressed together using a flip chip bonder equipped with a pulseheat function, followed by thermal compression bonding with pulseheating at 240° C. Thereafter, the composition A was cured in an oven at150° C. for 1 hour to complete an electronic device C.

(Electrical Continuity Test)

The electrical continuity of the above produced electronic device C wasexamined to find that the electrical continuity was good with respect toany heat exposure time on the hot plate at 80° C. (Table 3). Namely, allof the 544 bumps on the semiconductor chip were connected. Therefore, itwas demonstrated that the composition in Example 1 maintained liquiditysufficient for processing, even if the same was left standing on a hotplate at 80° C.

TABLE 3 Time for being left Electrical continuity  0 minutes good 15minutes good 30 minutes good 45 minutes good 60 minutes good 90 minutesgood

Examples 2 to 13

Electronic devices were produced by the same method as in Example 1,except that the components to be blended in the compositions werechanged as shown in Table 2. Also in Examples 2 to 13, circuitsubstrates coated with the compositions were left standing at 80° C. for0 min, 15 min, 30 min, 45 min, 60 min, and 90 min, then electronicdevices were produced, and the electrical continuity thereof wereexamined. As the results, for all the cases, good electrical continuitywas obtained. Therefore, it was demonstrated that the compositions inExamples 2 to 13 also maintained liquidity sufficient for processing,even if the same were left standing on a hot plate at 80° C.

Comparative Example 1

An electronic device was produced by the same method as in Example 1,except that the components to be blended in a composition were changedas shown in Table 2 and a maleimide compound and component (c) were notblended. Also in Comparative Example 1, circuit substrates coated withthe composition were left standing at 80° C. for 0 min, 15 min, 30 min,45 min, 60 min, and 90 min, then electronic devices were produced, andthe electrical continuity thereof were examined. As the results, goodelectrical continuity of an electronic device produced without beingleft standing at 80° C. (heat exposure time 0 min) was confirmed,however in all other cases, electrical continuity was not established(Table 4). Therefore, it was demonstrated that curing of the compositionin Comparative Example 1 had progressed by being left standing at 80°C., and good electrical continuity could not be established.

TABLE 4 Time for being left Electrical continuity  0 minutes good 15minutes unconnected 30 minutes unconnected 45 minutes unconnected 60minutes unconnected 90 minutes unconnected

Comparative Example 2

An electronic device was produced by the same method as in Example 1,except that the components to be blended in a composition were changedas shown in Table 2 and component (c) was not blended. Also inComparative Example 2, the electrical continuity was examined as inExample 1. As the results, good electrical continuity of an electronicdevice produced without being left standing at 80° C. (heat exposuretime 0 min) was confirmed, however in all other cases (left standing at80° C.), electrical continuity was not established. It was confirmedthat curing of the composition in Comparative Example 2 had alsoprogressed by being left standing at 80° C., and good electricalcontinuity could not be established.

Comparative Example 3

An electronic device was produced by the same method as in Example 1,except that the components to be blended in a composition were changedas shown in Table 2 and component (c) was replaced with benzoquinonewhich is a polymerization inhibitor. Also in Comparative Example 3, theelectrical continuity was examined as in Example 1. As the results, goodelectrical continuity of an electronic device produced without beingleft standing at 80° C. (heat exposure time 0 min) was confirmed,however in all other cases (left standing at 80° C.), electricalcontinuity was not established. It was confirmed that curing of thecomposition in Comparative Example 3 had progressed by being leftstanding at 80° C., and good electrical continuity could not beestablished.

Comparative Example 4

An electronic device was produced by the same method as in Example 1,except that the components to be blended in a composition were changedas shown in Table 2 and component (c) was replaced with hydroquinonewhich is a polymerization inhibitor. Also in Comparative Example 4, theelectrical continuity was examined as in Example 1. As the results, goodelectrical continuity of an electronic device produced without beingleft standing at 80° C. (heat exposure time 0 min) was confirmed,however in all other cases (left standing at 80° C.), electricalcontinuity was not established. It was confirmed that curing of thecomposition in Comparative Example 4 had progressed by being leftstanding at 80° C., and good electrical continuity could not beestablished.

1. A sealant composition for electronic device comprising: (a) acompound having two or more (meth)acryloyl groups and (c) a nitroxidecompound and/or a thiocarbonylthio compound.
 2. The compositionaccording to claim 1, further comprising a radical initiator.
 3. Thecomposition according to claim 1, further comprising (b) a maleimidecompound.
 4. The composition according to claim 3, wherein the maleimidecompound (b) comprises a bismaleimide.
 5. The composition according toclaim 1, which is used as an underfill sealant.
 6. The compositionaccording to claim 1, which is used in flip chip mounting.
 7. Anelectronic device comprising a cured product of the compositionaccording to claim
 1. 8. An electronic appliance comprising theelectronic device according to claim 7.